But surely an advanced civilization would realize theres less advanced lifeforms and would thus send the simplest type of message possible. After contact is established, they could then send their ultra-compressed data.

Or being advanced, this civilization would be extremely cautious of any other civilization, and would most likely not facilitate communications with others.

For a civilization to survive and be qualified as being advanced, not only implies being smart enough to develop some technology but smart enough to know when NOT to use it. e.g.: let's not use nuclear warheads, let's not use grey goo, let's not communicate with possibly agressive alien civilizations.

Why? We don’t simplify high bandwidth satellite radio signals for the benefit of the Sentinelese people, and unlike extra terrestrial life we can be certain that the Sentinelese are sentient, and also that they can (given enough time, but less than even a RTT to Andromeda) learn both how to tune in and what the signals we’re broadcasting ultimately mean.

That just depends on the delta between civilizations. They might've advanced way beyond us and they don't have the means to fallback to human method of communicating.